Frankly, my initial reaction to the doom-laden reports that BBC4 faces cuts in both its budget and the range of its output is to dismiss them as another example of clumsy spin.
If I had a pound for every bit of the BBC that’s been threatened with closure in the last eighteen months, only to be reprieved at the last minute, I’d have… well, about seven pounds.

And there’s a pattern. Threaten something with a small, but loyal audience. Watch that audience rise up in polite fury. Make a grand show of saving the threatened service, highlighting how much audiences love their favourite bits of the BBC.

My biggest worry, though, is that this time, they might actually be serious.

Like the bizarre suggestion of scrapping 6 Music, slicing up BBC4 makes little financial sense. Its annual budget, just over £50m, is about 5-percent of the money spent on BBC1 each year.

As targets go, you couldn’t pick one more tightly attuned to traditional public service values.

The real source of middle-class indignation is the idea that BBC3 might get off lightly from the round of cuts. Just read some of the comments on The Guardian’s website, to get a flavour of how the BBC’s most natural constituency view the home of Snog, Marry, Avoid.

With respect, many have missed the point. BBC4 viewers are, let’s be honest, pretty keen BBC consumers anyway. They watch Newsnight, listen to Radio 4, get their breaking news from the BBC website. They cheerfully hand over their licence fee every year.

BBC3 viewers, as a whole, do not live in that world. They watch ITV2 and E4, and rarely engage with news or documentaries.

Unless, of course, they’re presented differently. Like, say, the way BBC3 does. Many of the channels’ critics appear never to have actually watched it. It’s not just the home of Family Guy and Doctor Who re-runs, but documentaries like Our War.

It’s tried to engage young voters with the Question Time format, and broken new writing and performing talent in comedy and drama.

OK, not everything works. But BBC3 does a critical job for the corporation’s future – reaching out to the next generation of licence fee-payers, showing them the value of publicly-funded broadcasting.

So why must this debate be conducted in this way? BBC3 versus BBC4 – an ill-tempered battle in which only one can survive. Why can’t both survive? Both do equally important jobs. In a world of three-hundred TV channels, both are unique.

A more interesting question is, what now is the purpose of BBC2? Twenty years ago, it was to not be BBC1, but so many of what used to be its genres (youth programmes, new comedy, arts, foreign films) have been hived off to the digital channels that it’s hard to see what’s left.

Yes, there’s still Newsnight, comedy like Psychoville, the superb Stewart Lee (though hidden away at almost midnight), Adam Curtis’ exemplary documentaries. But there’s also a lot of filler, quizzes, lifestyle programmes that wouldn’t look out of place on ITV.

BBC2’s supposedly facing big cuts too – possibly losing much of its daytime output. Maybe a merger with BBC4 could work. If BBC2 was freed to genuinely innovate, and aim for slightly higher ground, it could absorb much of BBC4’s output, exposing it to a wider audience.

If that's not a goer, then surely managers will have to save BBC4. But not at the cost of BBC3. Instead, well-meaning letter-writers might want to ask why the Corporation is spending the equivilent of almost half BBC4's annual budget on the rights to yet another talent show.

Meanwhile, the Government helps itself to a significant chunk of the licence fee - enough for many years of BBC4 - to fund rural broadband roll-out. An admirable aim, but not strictly speaking the BBC's job.

Of course, this whole thing could be another one of Mark Thompson’s shroud-waving exercises. An announcement on cutbacks is due in late September. The polite-but-firm middle-classes are already sharpening their pencils….